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REBECCA LISSNER is Senior Fellow for U.S. Foreign Policy at the Council on Foreign Relations. She served as Deputy Assistant to the President and Principal Deputy National Security Adviser to the Vice President during the Biden administration.
MIRA RAPP-HOOPER is a Visiting Senior Fellow at the Brookings Institution. She was Special Assistant to the President and Senior Director for East Asia and Oceania and Director for Indo-Pacific Strategy at the U.S. National Security Council during the Biden administration.
They are the authors of An Open World: How America Can Win the Contest for Twenty-First-Century Order.
Trump’s War on Iran Reveals a Foreign Policy Without Principles
Rebecca Lissner and Mira Rapp-Hooper
Throughout U.S. President Donald Trump’s most recent campaign and second term in office, he and his team have attempted to spin his foreign policy as pragmatic, disciplined, and strategic. They counter accusations that his global approach is impetuous and reckless with professions of “flexible realism”––a nod to an intellectual tradition often traced back to Greek historian Thucydides, who famously observed that “the strong do what they can and the weak suffer what they must.” Though a diverse school of thought, realism generally holds that power is the currency of international politics. It eschews idealism and counsels a ruthless focus on defending national interest. The seeming resonance of this worldview with Trump’s early-second-term foreign policy has led prominent analysts to embrace realism as the unifying framework for the president’s heterodox approach. The New York Times even proclaimed it “the theory that gives Trump a blank check for aggression.”
But the United States’ new war with Iran makes clear that Trump is not a realist. In fact, realism, when properly understood, reveals the profound dangers of the Trump administration’s careening approach to foreign policy. Unleashing regional war in the Middle East with neither a compelling justification nor a theory of how best to advance U.S. interests is profoundly at odds with the core tenets of realism. Indeed, with his war with Iran, Trump has permanently ceded his claim to represent a clear-eyed and pragmatic approach to U.S. foreign policy, opening new space for other political leaders to take up that mantle.
In search of an intellectual framework to explain Trump’s worldview, the administration and commentators alike have turned to realism. The realist tradition has roots that run through U.S. presidents as diverse as John Quincy Adams, Dwight Eisenhower, and George H. W. Bush, as well as prominent thinkers including Hans Morgenthau, Kenneth Waltz, and John Mearsheimer. Academic realists have spent decades questioning whether states seek security or maximum power, under what conditions alliances are beneficial or entangling, and whether the post–World War II liberal international order was anything more than window dressing for American hegemony. They also readily acknowledge that intellectual realism doesn’t easily translate into clear prescriptions for U.S. foreign policy.
Realists of all stripes also counsel a certain national security pragmatism: secure a favorable balance of power and avoid peripheral conflicts that drain blood and treasure. Tied in is the importance of prioritizing national interest, and a wariness of unintended consequences, particularly in times of war. Across his two terms as president, analysts have labeled Trump a realist for different reasons at different times. One wave of commentary, prevalent in his first term, anointed Trump a realist precisely because of his perceived restraint. Trump claimed to reject prolonged and costly conflicts in the Middle East, and this anti-interventionism helped propel him to the White House in 2016. Under the tagline of “principled realism,” the first Trump administration was unapologetic in its pivot away from the Middle East and toward competition with China—a focus on great-power dynamics that most realists would expect to see from the United States facing a peer competitor. Anticipating a second Trump presidency, the prominent realist scholar Randall Schweller (writing with Andrew Byers) predicted in Foreign Affairs that Trump’s realist impulses would result in “the most restrained U.S. foreign policy in modern history.” These early assertions of Trump as a realist assumed a judiciousness and focus on great-power politics that many scholars and analysts believed had been missing from U.S. foreign policy for some time.
Trump’s second-term foreign policy quickly defied these expectations. In abandoning both military restraint and the strategy of great-power competition, the current Trump administration has pivoted to what it calls “flexible realism.” Anchored in the principle that might makes right, this new approach seems designed to justify the president’s expansive use of coercion. After the 2025 National Security Strategy put forth flexible realism as a basic principle, Trump called his January snatch-and-grab of Venezuelan President Nicolás Maduro an expression of “the iron laws that have always determined global power.” White House adviser Stephen Miller picked up on this theme, telling CNN that “we live in a world, in the real world . . . governed by strength, that is governed by force, that is governed by power.” Later that month, the 2026 National Defense Strategy heralded the president’s flexible, practical realism. “Out with utopian idealism,” it boldly proclaimed, and “in with hardnosed realism.” By March, in the early days of the war with Iran, Secretary of Defense Pete Hegseth attempted to justify the conflict in realist terms: “Our ambitions are not utopian; they are realistic, scoped to our interests and the defense of our people and our allies.”
There may be echoes of realism in Trump’s muscular approach, such as his focus on exercising military might and securing economic resources. But a penchant for power, unmoored from strategy or a clear definition of the national interest, does not qualify a leader as realist. And a proper reading of realism proves this description of Trump has not held up over time.
Realists pride themselves on their keen sense of strategy and laser focus on the requirements of great-power competition. Trump’s war of choice against Iran should permanently debunk the notion that he is the natural heir to the realist foreign policy tradition. Where realism counsels discipline, the Iran war represents the opposite. The conflict will have cost American taxpayers at least $20 billion by late March, despite the Trump administration finding it difficult to point to any imminent danger. The operation further embroils the United States in a region that Trump himself designated a lower strategic priority, particularly compared with the Indo-Pacific and Western Hemisphere. And the continued strikes could compromise the U.S. military’s near- and medium-term readiness by burning through vital munitions and relocating key strategic assets like missile defense systems and radars, weakening the United States’ preparedness for potential conflicts with China or Russia and even eroding deterrence.
The conflict in Iran violates some of the core precepts of realism. Realist thinkers would reject regime change as a worthy goal, as many did during the wars in Vietnam and Iraq, because they believe that the material power of a country matters much more than its internal character and that the costs of changing that character are often prohibitively high. For many years, Trump himself seemed to embrace this view, declaring during a visit to Saudi Arabia last year that “Western interventionists” and “nation builders wrecked far more nations than they built.” This sentiment was echoed in the 2026 National Defense Strategy, which proclaimed that the Department of Defense would no longer “be distracted by interventionism, endless wars, regime change, and nation building.” And yet regime change was central to the argument Trump made for launching the war in Iran, calling on Iranians to “take over” their government following the U.S. attack. Targeting decisions by the U.S.-Israeli coalition have matched this rhetoric, with an initial strike that eliminated Supreme Leader Ali Khamenei and many members of his inner circle, followed by an ongoing campaign that seems designed to fatally weaken the Iranian regime.
Even as the Trump administration has signaled it may be abandoning regime change as its objective, it has yet to articulate a theory of victory based on clearly defined national interests that marry available means with achievable ends. And as realists have recognized for centuries, without an understanding of how the use of force can translate into desired political outcomes, the risk of political failure in conflict is unacceptably high. While Trump’s strikes on Iranian nuclear facilities last year and his Venezuela raid seemed to be short, sharp, and self-contained uses of force that the school of offensive realists might have sanctioned as power-maximizing behavior, the new Iran war has already become a major regional conflagration with widespread destruction, cascading economic impacts, mounting U.S. losses, and the possible commitment of U.S. ground troops. Trump will at some point declare that his mission is accomplished, but it likely won’t be because the United States has achieved its political goals in the country.
Furthermore, early signs indicate that the administration rushed headlong into the conflict without accounting for the escalation dynamics that were likely to ensue. It was predictable that Tehran would widen the scope of the conflict by striking its Gulf neighbors—yet the administration waited four days after hostilities commenced before ordering U.S. diplomats in the region to evacuate. When asked why embassies had not been evacuated before strikes began, Trump explained that “it all happened very quickly,” suggesting that despite weeks of preparation, the administration had not anticipated these dynamics. It was just as obvious that Tehran would raise the global costs by targeting oil tankers in the Strait of Hormuz and creating an energy crisis—and yet Trump appeared surprised when oil prices spiked, quickly signaling that the war would end soon before walking those statements back and asking U.S. allies and partners, and even China, to help defend the strait.
The war in Iran is not the only evidence that Trump is not a realist. Where realism counsels the judicious use of power in pursuit of the national interest, Trump’s second-term foreign policy is doing the opposite. He has distanced himself from great-power competition with China and instead appears to be seeking a commercial peace with Beijing. His ability to maintain deterrence in the Indo-Pacific, meanwhile, has been undercut by the Iran gambit and its drain on military materiel and readiness. Although Trump has maintained U.S. alliance commitments, he is weakening their efficacy by calling into question Washington’s willingness to come to the defense of its allies. And far from maintaining a disciplined use of military force, Trump has overseen the bombing of seven countries in just one year.
Trump may believe that might makes right, but to the extent that his administration fits into any realist theory, it is in its blatant disregard of realism’s abiding warning that hegemons should avoid costly overextension. Indeed, with its reckless use of American power, the second Trump administration has become realism’s latest cautionary tale.
Debunking Trump’s claim to realism is more than an academic exercise. His critique of so-called globalist elites, his professed foreign policy restraint, and, above all, his opposition to U.S. military interventions overseas have always been intrinsic to Trump’s political brand. The “Make America Great Again” movement has long claimed noninterventionist foreign policies, and Vice President JD Vance pledged his fealty to Trump on the basis that he would not begin any new wars. Across multiple campaigns, that orientation proved remarkably popular with the American electorate.
Herein lies the opportunity for those who oppose Trump’s war as well as for the politicians and policymakers who come after him. There is a genuine public demand for a more disciplined, pragmatic approach to U.S. foreign policy. Trump’s war is not merely reckless because it ignores congressional war powers, international law, or the value of allied cooperation. It is reckless because it exemplifies the warmongering excesses that Americans have consistently decried because of their wasting effects on American power.
Making this case to the American people, especially as Trump raises up the realist mantle, requires resisting the pull toward the extremes. It might be tempting to reject Trump’s might-makes-right fixation in favor of a U.S. foreign policy that centers idealism and virtue. But an overly ideological foreign policy risks ensnaring the United States in the same trap it found itself in after the Cold War: when the United States acted primarily to advance its values and had no natural limits or disciplining boundaries.
On the other end of the spectrum, Trump’s national security excesses are leading some critics to amplify calls for a dramatically more restrained approach to U.S. foreign policy. Reckoning with fiscal and political constraints on foreign policy is a good thing, especially for a collection of political leaders and policymakers who grew accustomed to a U.S.-led unipolar era that has now passed. But in their enthusiasm to curb the U.S. military’s global reach and cut potentially entangling ties overseas, those who favor dramatic retrenchment could accelerate Trump’s thoughtless dismantling of U.S. power.
Instead, there is a more pragmatic and, indeed, realist path forward—one that leads toward a United States that is powerful, globally engaged yet disciplined, and, eventually, respected once again. And there is good reason to expect public support for it. According to Chicago Council surveys from 2024 and 2025, large majorities of Americans want the United States to have a strong global role with a foundation of close cooperation with allies. They recognize that, in an increasingly perilous world, there are opportunities the United States cannot afford to squander and threats it cannot afford to ignore. Realism after Trump, then, must meet that appetite with something Trump never offered: a coherent, affirmative vision for how American strength can be exercised with purpose, restraint, and strategic clarity to advance U.S. interests. With Trump’s Iran war at odds with each of these virtues, a more sensible and sober pathway is open for the taking.
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